A wandering black hole may have torn apart a star to create a strange object that brightened mysteriously and then faded from view in 2006, a new study suggests. But more than three years later, astronomers are still at a loss to explain all the features of the strange event.
The object, called SCP 06F6, was first spotted in the constellation Bootes in February 2006 in a search for supernovae by the Hubble Space Telescope. The object flared to its maximum brightness over about 100 days, a period much longer than most supernovae, which do so in just 20 days.
Further analysis of the object's spectrum in 2008 offered no more clues: SCP 06F6 seemed to resemble no known object, and astronomers couldn't even say whether the event originated in the Milky Way or beyond.
Examining the work over coffee, Boris Gaensicke of the University of Warwick in Coventry, UK, and colleagues noticed that dips in the object's light spectrum looked familiar. They resembled those created when light passes through a relatively cool area that is rich in carbon. "These wiggles are basically the fingerprints of carbon molecules," Gaensicke says.
Gaensicke and colleagues envision two scenarios that might explain the object. In one, a carbon-rich star gets too close to a middle- or heavy-weight black hole, which tears the star apart. Some of this material is absorbed by the black hole, and some is blasted away in a flare that was eventually seen from Earth as SCP 06F6.
Such flares brighten and dim with the same leisurely pace seen in SCP 06F6, and they also produce X-rays with a similar brightness to those the team found at the location of the firefly-like event.